U643B Flasher, 30-m Shunt Description The bipolar integrated circuit U643B is used in relaycontrolled automotive flashers where a high-level EMC is required. Lamp outage is indicated by frequency doubling during hazard warning as well as direction mode. Features Minimum lamp load for flasher operation: ≥ 1 W Temperature and supply voltage compensated flashing frequency Very low susceptibility to EMI Frequency doubling indicates lamp outage Protection according to ISO/TR 7637/1 level 4 Relay driver output with high current carrying capacity and low saturation voltage Block Diagram + VS + 49 6 C1 Measuring comparator K 1 V6–81 mV 20 k K1 4 2 R3 Shunt 5 k 30 m 7 K2 Pulse generator R1 3 49 a–Comparator K2 20 k 49 a–Comparator K3 Relay 8 49 a K3 5 R2 1.5...2.2 k 23 V 20 k 5 k IC Ground 1 R4 95 9756 470 5 W 21 W 21 W 21 W 21 W 5 W Indicator lamps GND – 31 Figure 1. Application circuit as a car flasher, Resistor R1 and R2: 1/4 Watt R4 for protection against continuous reversed polarity: 0.5 Watt Ordering Information Extended Type Number Package U643B DIP8 U643B-FP SO8 Rev. A3, 10-Apr-01 Remarks 1 (5) U643B Pin Description Pin Symbol Function 1 GND 2 VS 3 REL Relay driver 4 OSC C1 Oscillator 5 OSC R1 Oscillator 6 VS Supply voltage VS 7 LD Lamp failure detection 8 SI Start input (49a) IC ground GND 1 8 SI 7 LD REL 3 6 Vs 4 5 OSC Supply voltage VS VS 2 U643B OSC 94 9290 Figure 2. Pinning Functional Description Pin 1, GND The integrated circuit is protected against damage via resistor R4 to ground (–31) in the case of battery reversal. An integrated protection circuit together with external resistances R2 and R4 limits the current pulses in the IC. Pin 2, Supply voltage, VS - Power The arrangement of the supply connections to Pin 2 must be so as to ensure that, on the connection printed circuit board (PCB), the resistance of VS to Pin 6 is lower than that to Pin 2. Pin 3, Relay control output (driver) The relay control output is a high-side driver with a low saturation voltage and capable to drive a typical automotive relay with a minimum coil resistance of 60 . Pin 4 and 5 Oscillator Flashing frequency, f1, is determined by the R1C1 components as follows (see figure 1): f1 where 1 Hz R1 C1 1.5 C1 47 F R1 6.8 k to 510 k In the case of a lamp outage (see Pin 7) the oscillator frequency is switched to the lamp outage frequency f2 with f2 2.2 f1. Duty cycle in normal flashing mode: 50% Duty cycle in lamp outage mode: 40% (bright phase) Pin 6, Supply voltage, Sense For accurate monitoring via the shunt resistor, a mini- 2 (5) mized layer resistance from point VS / shunt to Pin 6 is recommended. Pin 7, Lamp outage detection The lamp current is monitored via an external shunt resistor R3 and an internal comparator K1 with its reference voltage of typ. 81 mV (VS = 12 V). The outage of one lamp out of two lamps is detected according to the following calculation: Nominal current of 1 lamp: 21 W / (VS = 12 V): Ilamp = 1.75 A Nominal current of 2 lamps: 2 x 21 W / (VS = 12 V): Ilamp = 3.5 A. The detection threshold is recommended to be set in the middle of the current range: Ioutage 2.7 A Thus the shunt resistor is calculated as: R3 = VT (K1) / Ioutage R3 = 81 mV/2.7 A = 30 m. Comparator K1‘s reference voltage is matched to the characteristics of filament lamps (see “control signal threshold” in the data part). The combination of shunt resistor and resistance of wire harness prevents Pin 7 from a too high voltage in the case of shorted lamps. Pin 8, Start input Start condition for flashing: the voltage at Pin 8 has to be below K3 threshold (flasher switch closed). Humidity and dirt may decrease the resistance between 49 a and GND. If this leakage resistance is 5 k the IC is still kept in its off-condition. In this case the voltage at Pin 8 is between the thresholds of comparators K2 and K3. During the bright phase the voltage at Pin 8 is above the K2 threshold, during the dark phase it is below the K3 threshold. For proper start conditions a minimum lamp wattage of 1 W is required. Rev. A3, 10-Apr-01 U643B Absolute Maximum Ratings Reference point Pin 1 Parameters Symbol Value Unit VS 16.5 V IFSM IFSM IFSM IO 1.5 1.0 50 0.3 A A mA A Ptot Ptot Ptot Ptot 420 340 690 560 mW mW mW mW TJ 150 °C Ambient temperature range Tamb –40 ... + 95 °C Storage temperature range Tstg –55 ... + 150 °C Symbol Value Unit RthJA RthJA 110 160 K/W K/W Supply voltage Pin 2 and 6 Surge forward current tP = 0.1 ms Pin 2 and 6 tP = 300 ms Pin 2 and 6 tP = 300 ms Pin 8 Output current Pin 3 Power dissipation Tamb = 95°C DIP 8 SO 8 DIP 8 SO 8 Tamb = 60°C Junction temperature Thermal Resistance Parameters Junction ambient DIP8 SO8 Electrical Characteristics Typical values under normal operation in application circuit (see figure 1), VS (+49, Pin 2 and 6) = 12 V. Reference point ground (–31), Tamb = 25°C, unless otherwise specified Parameters Test Conditions / Pins Symbol Pin 2 and 6 VS (+49) 9 to 15 IS IS 44.55 7.0 Supply voltage range Supply current: Pin 3 IO = 150 mA, VS= 9 V with resistance = 60 reverse current Start delay First bright phase Frequency tolerance Bright period Basic frequency f1 Control frequency f2 Frequency increase Lamp outage Control signal threshold VS = 15 V VS = 9 V VS = 12 V Leakage resistance 49a to GND Lamp load Rev. A3, 10-Apr-01 Typ. Max. Unit V Pin 2 and 6 Dark phase Bright phase Relay output: saturation voltage Min. Pin 7 Pin 7 Pin 7 8 11 mA mA VO IO 1.0 0.1 V mA ton 10 ms f1 –5 +5 % ∆f1 ∆f2 47 37 53 45 % % f2 2.15 f1 2.3 f1 Hz VR3 VR3 VR3 85 66 76 91 71 81 97 76 87 mV mV mV 4 5 k RP PL 1 W 3 (5) U643B Package Information Package DIP8 Dimensions in mm 9.8 9.5 1.64 1.44 7.77 7.47 4.8 max 6.4 max 0.5 min 0.58 0.48 3.3 0.36 max 9.8 8.2 2.54 7.62 8 5 technical drawings according to DIN specifications 13021 1 4 Package SO8 Dimensions in mm 5.2 4.8 5.00 4.85 3.7 1.4 0.25 0.10 0.4 1.27 6.15 5.85 3.81 8 0.2 3.8 5 technical drawings according to DIN specifications 13034 1 4 (5) 4 Rev. A3, 10-Apr-01 U643B Ozone Depleting Substances Policy Statement It is the policy of Atmel Germany GmbH to 1. Meet all present and future national and international statutory requirements. 2. Regularly and continuously improve the performance of our products, processes, distribution and operating systems with respect to their impact on the health and safety of our employees and the public, as well as their impact on the environment. It is particular concern to control or eliminate releases of those substances into the atmosphere which are known as ozone depleting substances (ODSs). The Montreal Protocol (1987) and its London Amendments (1990) intend to severely restrict the use of ODSs and forbid their use within the next ten years. Various national and international initiatives are pressing for an earlier ban on these substances. Atmel Germany GmbH has been able to use its policy of continuous improvements to eliminate the use of ODSs listed in the following documents. 1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments respectively 2. Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental Protection Agency (EPA) in the USA 3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C (transitional substances) respectively. Atmel Germany GmbH can certify that our semiconductors are not manufactured with ozone depleting substances and do not contain such substances. We reserve the right to make changes to improve technical design and may do so without further notice. Parameters can vary in different applications. All operating parameters must be validated for each customer application by the customer. Should the buyer use Atmel Wireless & Microcontrollers products for any unintended or unauthorized application, the buyer shall indemnify Atmel Wireless & Microcontrollers against all claims, costs, damages, and expenses, arising out of, directly or indirectly, any claim of personal damage, injury or death associated with such unintended or unauthorized use. Data sheets can also be retrieved from the Internet: http://www.atmel–wm.com Atmel Germany GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany Telephone: 49 (0)7131 67 2594, Fax number: 49 (0)7131 67 2423 Rev. A3, 10-Apr-01 5 (5)